Cathode-ray tube



July 15, 1952 ANGELL 2,603,761

CATHODE-RAY TUBE Filed May 2, 1951 Wa/te; E. Ange INVENTOR.

w mw Patented July 15, 1952 UNITED STATES. PATENT OFFICE CATHODE-RAY TUBE v .WaltedErAngell,BrooklymNtY,

. AppIicationMa-YZ, 195 11,;seria1,n ,;2a4;c9r

"This inyen'tion relates to electron beam or cathode ray tubes, such as 'usedfor oscillographs,

television-tubes-or'the like"an'dit has forits primary'object to provide an elec'tro'n beam ortca'thod'e ray tube which "has a, longer lifetime and is less subject to destruction by accident than tubes of the standardconstructioni- A "beam electrode or cathode ray "tubes-are rather expensive 'uni'ts and their lifetimeis largely "governed by the lifetime fof the heated According to the invention the cathode ray tube is provided with 'two --cathode filaments which may be used alternatively for producing the electron emission of the tube :and the changeover from --one cathode filament tothe other is produced by 'a switch *built into the socket of the tube in such a manner that neither the switchnor the handle-of the same protrudes to -a marked extent, thus permitting "to insert the tube into any socket -andintoany assembly between parts so spaced and-arranged 'thatthey will accommodate a conventional tube of the same -type and size. Whileattention' may be paid to locate the switch preferably at a point which is usually---accessibleand not obstructed by other parts -of the set, it is not im- "perativeto make special provisions, as the tube 'may be removed, if need be, for the switching operating 'and 'may afterwards be replaced.

The principal object-of the inventionistherefore to provide an electron beam or cathode ray tubewith morethan one filament and with means for switching in a filament kept in reserve as soon-as the filament originally used is .destroyed or has disintegrated or is thought to be less effective than expected.

A further object of the invention consists in arranging the switching means in such a manner that they are completely contained within i-t'he socket of the tube with "practically no-mart fprojecting or protruding f'rom the socket 'and with practically 'no change in the appearance or in the outline of the socket.

' Afurther object -of-the invention consists in keeping the socket substantially closed after the lamp has been fixed within the socket so as to exclude the intrusion of extraneous objects or particles, even of small particles, such as dust or other particles floating in the air after the tube has been fixed to the socket.

recla ms. (crisis-is) Further *objects of 'the invention will'be apparent fromthe following detailed specification.

The invention is illustrated in' the accompanying drawing by way of example'on'ly. Only-one embodiment of "the invention is shown in the accompanying drawing, but it is to "be'understood that the embodiment shown was selected for the purpose of --explaining' the principle of v the inventionand the best mode of applying-said principle. 'No survey of "the possible embodiments of the invention is given in the specification and a departure from the-example shown in the drawing is therefore not necessarily'a' departure from theprinciialeo'f the'inven'tion.

In the drawing: Figure 1 is an elevational view of the-lower "portion of a cathode ray tube.

' Figure '2 is a =sectional-elevational fractional view through the lower part of 'a cathode ray tube on an enlarged scale.

which it is fixed. The bottom portion I-2 of said socketcarries the base pins I 5, -l-6- of which only two are shown. *Thetube "i0 is "shown'as being provided with two filament-s18, '20 joined bya conductorlfi to each other while eachfilament 'is moreover in addition provided with a "separate connection 21, '22; "respectively, each leading; to acontact 24, 25, respectively.

These contacts are preferably buttonsformed bythe head of screw bolts -(not shown) screwed into-threaded holes of the sockets andJ-the'said heads mayrest upona washer or contact-plate 26. The "two contacts -24,'--2'5 "are suitably spaced and are arranged in the interior 5015 the socket so that the wires 2 l, 22 leading from the filaments maybe easily fixed and soldered to them. Above these two contacts 24, '25 the socket l l is prbvidedwith a narrow slot =30 1eading-irom the interior 'o'fthe socket into a recess 31 "provided onthe outside of the socket. This recess is preferably cross-shaped with "an elongated middle section 35 and with-much 1 narrower upper and lower extensions 33. The portions of the socket which are adjacent to the said middle portion 35 and to the extensions 33 are preferably provided with undercuts 34 adjoining to the middle portion of the recess and reaching to. one of thebase pins l5. .longenough and must be so bent-or coiled that p out putting a strain on tions.

from the extensions to the ends of said middle portion. A slide 36 which may also be crossshaped may be placed into the recess 3|. The middle portion 38 of the slide may have approximately the thickness of the recess 3| or a thickness slightly in excess of the same and the outer surface of the slide may be roughened or slightly corrugated to facilitate manipulation of the slide. The two "upwardly and downwardly projecting wind portions 39 of the slide are of a reduced thickness corresponding to the width of the undercuts 34 and their length is preferably substantially equal to the width of the upper and lower extensions 33 of the recess 3 I.

The slide may be made of a material identical tiple filament, the individual filaments being switched in or out as desired by the operator of the tube, while at the same time the outline and appearance of the socket and the general construction remains unchanged. The user of the cathode ray tube may therefore, by substituting one filament for the otherwhen burned out or broken, obtain a longer lifetime for the rather expensive tubethan this vwas'possible with the tubes as now used whileno special provision need be made to accommodate the tube according to the invention.

with that of the socket, which isusually pressed.

from molded plastic material, and carries on its backside a contact spring in the shape of an elastic tongue 40 whichf'may have a tip embedded and firmly anchored within the plastic material of the slide 36. The contact spring or tongue 40 passes through'the slot3|lin the socket and the tip'of the tongue may be provided with a depression or with a hole and may engage one of .thecontact buttons 24, 25. To this contact spring or tongue the end of a wire 42 is-soldered,

the other end of which'isattached and soldered The wire must be a limited movement of the slide is permitted withthe soldered end connec- The resilient tongue or contact spring 40 moves with the slide and in the two end positions of the same makes contact with the two contact buttons 24, 25. The depression or hole serves to produce fixation of the tongue and of the slide insuch an end position without preventing movement of the slide if some lateral force is applied .to thecorrugated outer surface of the slide portion which is approximately flush with the outer surface of the socket.

The slide maybe fitted into the recess 3| by threading the tongue 40 through the slot 30 while the slide is in the center of the recess and the .wings 39 of the slide fit exactly over the cuts or extensions 33 thus permitting the slide to enter into the recess 3| completely with the outer surface of the slide 36 flush with the socket. When,

I thisposition has been reached the slide may be displaced laterally to the right or to the left and during such displacement the wings 39 of the slide will enterthe undercuts 34 and the slide will be guided during its movement by the said undercuts and will -be held in its place. When,

moved to one end of the recess the tongue 40 engages one of the contacts buttons 24 or,25 according to the position of the slide. As seen from Figure 4, if one of the base pins lfi-iscon nected with the wire I9 joining the two filaments l3 and 20 th movement of the contact spring 40 on the slide and its, contact with one of the two buttons -24 and 25 will determine which filament .is connected with the source of current. If

the filament hasto be changed, pressure is applied on the outer side of the slide 36 and the latter'ismerely moved to the other sideof the slot where it engages the other contact.

From the above it will be seen that the invention provides a cathode ray tube with a mul- 7 Number It will also be understood that changes of unessential nature may be made without departing from. the essence of the invention as defined by the annexed claims.

Having described the invention, what is claimed as new is:

1. A cathode ray tube, comprising a cathode member including a plurality of heated alternatively active filaments, a cylindrical socket-surrounding the base of the cathode ray tube .and having an enclosed bottom'portio n and .an annular fiange into which the base of the said cathode ray .tube is inserted and in which it is firmly seated, thus providing a substantially closed space between said cathode ray tube, and said socket, base pins projecting from the bottom portion of said socket, two of the base pins being connectible with the cathode filaments, said socket being provided in its cylindrical portion with a recess on the outside and with a slot leading from the recess to the interior of the socket. a slide member adapted to move within said recess, a switching member projecting from said slide member through the slot in the socket into the interior. of the same, a plurality of fixed contacts on the inner. surface of the cylindrical socket, positioned so as to come into operative contactwith the switch member upon movement of the slide in the recess, and connections leading from each of said filaments to said contacts, said switch member being connected to one of the base pins in order to produce alternatively a contact between one of said base pins and one of said'heated filaments.

' '2. A cathode ray tube as claimed in claim 1 in which the recess in the outer surface of the socket is cross-shaped and the slide member is substantially of the thicknessqof the recesspand in which the socket is further provided with undercuts adjac-ent'to the cross-shaped recess, for guiding the slide member, while part of the surface of the slide member is exposed for manipuprotruding beyond the cylindricalsurface of the socket.

- WALTER E. ANGELL.

, REFERENCES CITED The following references are of record in the file of this patent:

' UNITED STATES PATENTS Name 7 Date 244,482; Perkins July 19, 1881 1,699,011 Murphy Jan. 15, 1929 1,722,002 Kuen et al.; July 23,1929 1,814,805 Hitchcock July 14, 1931 2,112,746 Wolfel Mar. 29, 1938 2,512,859

Smith June 27, 1950 

